Methods and systems for controlling staple firing

ABSTRACT

Systems and methods for controlling staple firing include an end effector, a drive system configured to apply a force or torque to cause staple firing to occur, and a processor. The end effector includes a first jaw and a second jaw holding staples. The processor is configured to monitor the applied force or torque to cause staple firing to occur and maintain application of clamping by the first jaw and the second jaw while suspending application of the force or torque that causes the staple firing, when the applied force or torque is outside an acceptable range of force or torque.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent application Ser. No. 15/836,506, filed Dec. 8, 2017, issued as U.S. Pat. No. 10,758,226, which is a continuation of U.S. patent application Ser. No. 14/949,827, filed Nov. 23, 2015, issued as U.S. Pat. No. 9,877,718, which is a divisional application of U.S. patent application Ser. No. 13/350,512, filed Jan. 13, 2012, issued as U.S. Pat. No. 9,226,750, and claims the benefit of U.S. Provisional Patent Application No. 61/443,148, filed Feb. 15, 2011, each of which is incorporated herein by reference in its entirety.

The present application is related to U.S. application Ser. No. 12/705,418 entitled “Cut and Seal Instrument,” filed on Feb. 12, 2010; U.S. Provisional Application No. 61/260,907, entitled “END EFFECTOR WITH REDUNDANT CLOSING MECHANISMS,” filed on Nov. 13, 2009; U.S. Provisional Application No. 61/260,903, entitled “WRIST ARTICULATION BY LINKED TENSION MEMBERS,” filed on Nov. 13, 2009; U.S. Provisional Application No. 61/260,903, entitled “WRIST ARTICULATION BY LINKED TENSION MEMBERS,” filed on Nov. 13, 2009; U.S. Provisional Application No. 61/260,915, entitled “SURGICAL TOOL WITH A TWO DEGREE OF FREEDOM WRIST,” filed on Nov. 13, 2009; and U.S. Provisional Application No. 61/260,919, entitled “MOTOR INTERFACE FOR PARALLEL DRIVE SHAFTS WITHIN AN INDEPENDENTLY ROTATING MEMBER,” filed on Nov. 13, 2009; each of which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

Minimally invasive surgical techniques are aimed at reducing the amount of extraneous tissue that is damaged during diagnostic or surgical procedures, thereby reducing patient recovery time, discomfort, and deleterious side effects. As a consequence, the average length of a hospital stay for standard surgery may be shortened significantly using minimally invasive surgical techniques. Also, patient recovery times, patient discomfort, surgical side effects, and time away from work may also be reduced with minimally invasive surgery.

A common form of minimally invasive surgery is endoscopy, and a common form of endoscopy is laparoscopy, which is minimally invasive inspection and surgery inside the abdominal cavity. In standard laparoscopic surgery, a patient's abdomen is insufflated with gas, and cannula sleeves are passed through small (approximately one-half inch or less) incisions to provide entry ports for laparoscopic instruments.

Laparoscopic surgical instruments generally include an endoscope (e.g., laparoscope) for viewing the surgical field and tools for working at the surgical site. The working tools are typically similar to those used in conventional (open) surgery, except that the working end or end effector of each tool is separated from its handle by an extension tube (also known as, e.g., an instrument shaft or a main shaft). The end effector can include, for example, a clamp, grasper, scissor, stapler, cautery tool, linear cutter, or needle holder.

To perform surgical procedures, the surgeon passes working tools through cannula sleeves to an internal surgical site and manipulates them from outside the abdomen. The surgeon views the procedure by means of a monitor that displays an image of the surgical site taken from the endoscope. Similar endoscopic techniques are employed in, for example, arthroscopy, retroperitoneoscopy, pelviscopy, nephroscopy, cystoscopy, cisternoscopy, sinoscopy, hysteroscopy, urethroscopy, and the like.

Minimally invasive telesurgical robotic systems are being developed to increase a surgeon's dexterity when working on an internal surgical site, as well as to allow a surgeon to operate on a patient from a remote location (outside the sterile field). In a telesurgery system, the surgeon is often provided with an image of the surgical site at a control console. While viewing an image of the surgical site on a suitable viewer or display, the surgeon performs the surgical procedures on the patient by manipulating master input or control devices of the control console. Each of the master input devices controls the motion of a servo-mechanically actuated/articulated surgical instrument. During the surgical procedure, the telesurgical system can provide mechanical actuation and control of a variety of surgical instruments or tools having end effectors that perform various functions for the surgeon, for example, holding or driving a needle, grasping a blood vessel, dissecting tissue, or the like, in response to manipulation of the master input devices.

Non-robotic linear clamping, cutting and stapling devices have been employed in many different surgical procedures. For example, such a device can be used to resect a cancerous or anomalous tissue from a gastro-intestinal tract. Unfortunately, many known surgical devices, including known linear clamping, cutting and stapling devices, have opposing jaws that may generate less than a desired clamping force, which may reduce the effectiveness of the surgical device. Devices have been developed generating higher levels of clamping forces for applicable surgical procedures (e.g., tissue stapling), however, clamping with high force jaws periodically fails. Additionally, firing of staples to seal tissue may fail. Detecting failure in clamping or firing of a staple has proven difficult in some minimally invasive surgical applications, however, since a surgeon may not have a clear view of the tissue being clamped or stapled and a tool inserted into a body is constrained by significant size and space limitations. Since a surgeon's tactile feedback in a robotic system can be somewhat limited, a surgeon may not realize when failure has occurred until after the clamping or firing procedure is complete. In light of the above, it would be desirable to enable a surgeon to detect clamping or failure at the time it occurs, so that the procedure can be suspended or modified to reduce the likelihood of tissue damage and/or to allow the surgeon to mitigate the effects of any tissue which has been damaged. Given the limitations associated with a minimally invasive surgical environment, it would be desirable to detect failure from outside the body without substantially adding to the profile of the end effector.

Thus, methods and system which can detect failure and indicate failure to the user, yet are compatible with the demands of minimally invasive procedures are desirable. Such tools may be beneficial in surgical applications, particularly in minimally invasive surgical applications.

BRIEF SUMMARY OF THE INVENTION

Improved systems and methods to detect and indicate clamping and/or staple firing failure are provided. The claimed methods and systems relate to detecting whether clamping of a material grasped between jaws or firing of a staple into the clamped material is likely to fail. The claimed systems and methods may detect failure in clamping or firing during the process of clamping or firing, thereby reducing the potential for tissue damage from continuing to clamp or fire a staple after failure has occurred. The claimed systems and methods are particularly useful in surgical applications involving clamping of a body tissue between two jaws of an end effector and firing of a staple into the clamped tissue. Many surgical applications require clamping of a body tissue at a clamping force sufficient for cutting, sealing and/or stapling of the clamped tissue. Since clamping and firing of a staple may require relatively higher forces than tissue manipulation, failure in clamping or firing may potentially cause damage to the delicate tissues. The present methods and systems are particularly advantageous in minimally invasive surgical applications as they indicate failure as soon as it occurs and allows for detection of failure from outside the body. While the various embodiments disclosed herein are primarily described with regard to surgical applications, these surgical applications are merely example applications, and the disclosed end effectors, tools, and methods can be used in other suitable applications, both inside and outside a human body, as well as in non-surgical applications.

In a first aspect, the invention provides a method of detecting failure in clamping of a material between jaws driven by a motor or detecting failure in firing of staple, the firing force being driven by an actuator, such as a motor. The method includes monitoring a drive parameter of the actuator or motor during application of a clamping or firing force and, in response to the monitored drive parameter, outputting an indication on a user interface of clamping or firing failure. Typically, an indication of clamping or firing failure occurs when the monitored drive parameter of the actuator, such as a torque output of a motor or displacement of a driving mechanism, is outside an acceptable range of drive parameters. The indication may also be indicative of a likelihood of clamping or firing failure, wherein the likelihood of failure falls within a gradient between a first and second likelihood, the first likelihood being likely failure and the second likelihood being likely success. In many embodiments, the material clamped and stapled is a body tissue, including an outer skin or internal organs, such as a bowel, stomach or lung.

In many embodiments, the methods and systems include monitoring a drive parameter during clamping between a first and second jaw of an end effector or during firing of a staple into clamped tissue. Often, the clamped tissue is cut after opposing sides of the tissue along the cutting line are stapled by a row of surgical staples to seal the tissue. The end effector is generally part of a minimally invasive robotic surgical system. The first and second jaw may comprise two separate jaws or a first jaw articulable against a portion of the end effector, in which case the portion of the end effector comprises the second jaw. In one aspect, the methods include clamping of a material between the first and second jaw of an end effector or firing of a staple into the clamped material, typically in response to a command from a user to clamp or fire. The system effects clamping or firing by applying a clamping force to a clamp or firing force to a staple. As the clamping or firing occurs, the system monitors the drive parameter of the actuator applying the clamping or firing force. In response to the monitored drive parameter, the system outputs an indication on a user interface of clamping or firing failure or the clamping or firing success.

In many embodiments, an indication of likely clamping or firing failure is provided in response to the monitored drive parameter being outside an acceptable range of desired drive parameters of the actuator, such as a range of torque outputs. Often, the acceptable range of drive parameters vary with the displacement of the actuator or motor, such that the acceptable range of drive parameters may be different depending on the configuration of the end effector. For example, the acceptable range of drive parameters at an initial displacement of the actuator or motor (as the clamp starts from an open configuration) may be different from the acceptable range of drive parameters at a final displacement (such as when the clamp is in a closed/clamped configuration). The same is true for the different initial configuration and final configuration of the firing mechanism. The system may detect the configuration of the end effector by sensing the displacement of the actuator effecting movement, or the mechanism through which the actuator effects clamping or firing. The clamping or firing is effected by the drive parameter through one or more mechanisms coupling the actuator to the end effector and/or the staple. The mechanism(s) may include a cable, a hypotube, or a leadscrew. In many embodiments, the indication of likely clamping failure is a visual indicator shown on a display of a user interface, but may also be communicated to the user by an audio signal, visual signal, or other sensory indicator.

In another aspect, a method or system may suspend driving of the actuator in response to an indication of failure or likely failure in clamping or firing of the staple. The methods may also include maintaining a driving parameter after an indication of failure, or maintaining a driving parameter driving clamping while suspending a force driving firing of a staple. In many embodiments, the clamping mechanism is non-backdriveable such that no input is needed to maintain the clamping force once it is applied or established. In such cases, an input may be needed to unclamp and reverse the motion of the leadscrew. The methods may include reversing a driving force so as to unclamp after outputting the indication of failure.

In many embodiments, the system includes an end effector, a sensor, and a user interface. A first and second jaw of the end effector are coupled to an actuator such that driving the actuator produces a clamping force so as to clamp a material between the first and second jaws. The system may also include an actuator, such as a motor, releasably coupled to a staple such that driving the actuator produces a firing force so as to fire the staple into the body tissue. The clamping and firing actuator may be a single actuator or may be separate actuators. The system may include a sensor for monitoring the drive parameters applying the clamping or firing forces to the end effector. The sensor may be a separate sensor or may be incorporated into the robotic surgical system and may also monitor a displacement of the motor or mechanism. The systems may also include a processor for comparing the monitored drive parameter with a desired drive parameter or range of parameters. The processor may also determine the range of acceptable drive parameters for a given displacement.

The system may comprise a first and second actuation mechanism for effecting clamping and firing, respectively. The first and second actuation mechanisms can employ different force transmission mechanisms corresponding with the force requirements for the clamping mode and the firing force mode. For example, a force used by the first jaw actuation mechanism to move the jaw from the open to the close position can include a linear force or a torque, and a force used by the second jaw actuation mechanism to fire a staple through the tissue can include a torque. In many embodiments, the first actuation mechanism includes a leadscrew-driven mechanism for use in the high force clamping mode, and the second actuation mechanism includes a second leadscrew-driven mechanism for use in the firing of the staple. Alternatively, the clamping and firing may utilize a portion of or the same mechanism.

For a fuller understanding of the nature and advantages of the present invention, reference should be made to the ensuing detailed description and accompanying drawings. Other aspects, objects and advantages of the invention will be apparent from the drawings and detailed description that follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a minimally invasive robotic surgery system being used to perform a surgery, in accordance with many embodiments.

FIG. 2 is a perspective view of a surgeon's control console for a robotic surgery system, in accordance with many embodiments.

FIG. 3 is a perspective view of a robotic surgery system electronics cart, in accordance with many embodiments.

FIG. 4 diagrammatically illustrates a robotic surgery system, in accordance with many embodiments.

FIG. 5A is a front view of a patient side cart (surgical robot) of a robotic surgery system, in accordance with many embodiments.

FIG. 5B is a front view of a robotic surgery tool.

FIG. 6A is a perspective view of an end effector having an articulated jaw, in accordance with many embodiments.

FIG. 6B is a perspective view of the end effector of FIG. 6A (with the articulated jaw removed to better illustrate leadscrew actuation mechanism components), in accordance with many embodiments.

FIGS. 7A and 7B illustrate components of a leadscrew actuation mechanism, in accordance with many embodiments.

FIG. 8A illustrates components of a cable actuation mechanism, in accordance with many embodiments.

FIG. 8B is a perspective view of the end effector of FIG. 8A with a portion of the articulated jaw removed to show cable actuation mechanism components disposed behind the articulated jaw, in accordance with many embodiments.

FIGS. 8C through 8F illustrate opposite side components of the cable actuation mechanism of FIG. 8A.

FIG. 9A is a perspective view illustrating a cable actuation mechanism, showing a cable used to articulate the jaw towards a clamped configuration, in accordance with many embodiments.

FIG. 9B is a perspective view illustrating the cable actuation mechanism of FIG. 9A, showing a cable used to articulate the jaw towards an open configuration.

FIG. 10 is a cross-sectional view illustrating components of a leadscrew actuation mechanism, in accordance with many embodiments.

FIG. 11 is a simplified diagrammatic illustration of a tool assembly, in accordance with many embodiments.

FIG. 12 is a simplified diagrammatic illustration of a robotic tool mounted to a robotic tool manipulator, in accordance with many embodiments.

FIG. 13 is a diagrammatic view of a telerobotic surgical system, in accordance with many embodiments.

FIGS. 14A-14B illustrate the user interface assembly having an clamping failure indicator, in accordance with many embodiments.

FIGS. 15A-15B illustrate examples of indicators of clamping failure indicators, in accordance with many embodiments.

FIGS. 16A-16B illustrates exemplary motor torques during clamping as compared to a range of acceptable motor torques which vary with motor displacement, in accordance with many embodiments.

FIGS. 17-20 illustrate methods, in accordance with many embodiments.

FIGS. 21-22 illustrate flow charts utilizing methods in accordance with many embodiments.

DETAILED DESCRIPTION

Improved systems and methods related to clamping and/or fastener firing are provided. The present invention relates to providing an indicator of whether clamping of a given material fails during clamping. The invention may be used in systems having jaw members for clamping a material or firing of a staple into a clamped material. The claimed system and methods are particularly useful for minimally invasive surgical applications, as they allow for failure detection in constrained environments from outside the body. Such systems often include end effectors having jaws that clamp a body tissue and fire a staple into the tissue at a relatively high force. Clamping at a high clamping force allows the user to perform various procedures requiring a hard clamp. For example, a physician may require a hard clamp of body tissues before cutting, sealing or stapling of tissue. Firing of staples or other fasteners may also require use of relatively high forces to drive the staple through the body tissue. Since clamping and staple firing utilize relatively high forces applied in a confined surgical area, clamping or firing failure has the potential to damage delicate tissues. The claimed methods and systems are advantageous as they allow detection of clamping or firing failure during the clamping or firing process from outside the body without increasing the profile of the end effector. Such methods and systems allow for increased capabilities and safety for the patient while maintaining the reduced scale of the minimally invasive surgical tools. While the various embodiments disclosed herein are primarily described with regard to surgical applications, these surgical applications are merely example applications, and the disclosed systems and methods can be used in other suitable applications, both inside and outside a human body, as well as in non-surgical applications.

Typically, a system utilizing the claimed invention includes an end effector having two jaws for clamping a material and/or firing a staple or fastener through the clamped material. The two jaws may comprise an articulated jaw attached to an end effector, such that moving the articulated jaw towards a portion of the end effector, the second jaw being that portion of the end effector. In many embodiments, the system uses two independent mechanisms to articulate the jaws of the end effector. A first actuation mechanism provides a fast response/low force mode that varies the position of the articulated jaw between a closed (grasped) configuration and an open configuration. In many embodiments, the first actuation mechanism is back-drivable. For example, in the low force mode grasping mode the first actuation mechanism can be designed to provide 5 lbs of clamping force between the tips of the first and second jaw. A second actuation mechanism provides a high clamping force mode for clamping the body tissue between the jaws at the higher clamping force. Often, the second actuation mechanism is non-back-drivable. The second actuation mechanism converts a relatively weak force or torque (but with large displacement available) to a relatively high torque rotating the jaw of the end effector. The second actuation mechanism can be designed to provide, for example, 50 pounds of clamping force between the tips of the clamped jaws.

Typically, in applications using the claimed methods, a surgeon clamps the body tissue at the relatively high clamping force and once clamped, fires a series of staples through the clamped tissue thereby sealing the tissue. Periodically, the jaws may fail to clamp the tissue, potentially resulting in damage to the tissue. Clamping of the tissue may fail for a variety of reasons, including too much tissue being grasped or insufficient tissue grasped between the jaws, including interference from an adjacent tissue, such as a bone, or slippage of the tissue from between the jaws. Even if clamping is successful, firing of a staple or other fastener may fail for a variety of reasons, including a jammed staple, inconsistencies in the material, interference from another material, or slippage of the clamped material. Therefore, it would be advantageous for systems and methods that can detect when clamping or firing failure occurs during the process of clamping or firing and indicate such failure to a physician, thereby reducing the likelihood that tissue damage will result. Ways in which tissue damage can be avoided by use of the claimed methods, include: terminating the clamping or firing process or allowing the user to terminate or modify the process after failure has been indicated. The described systems and methods detect such failures and provide an indication to the user of failure or likely failure during clamping and/or staple firing into a clamped material. Clamping may be considered successful when in the clamped position, the distance between the jaws are sufficient for performing a therapy, such as firing a staple through the clamped tissue. This distance may vary according to various factors, including the type of tissue, type of treatment, or the dimensions of a staple to be fired through the clamped tissue. In one aspect, the claimed methods and systems detect failure by monitoring a drive parameter of an actuator or motor that drives the clamping and/or staple firing. In a preferred embodiment, the motor provides a drive parameter or force output, such as a torque, to a mechanism so as to effect clamping and/or firing of a staple with the end effector. The system may determine whether the drive parameter is within an acceptable range of desired drive parameters. The acceptable range of drive parameters may vary according to the displacement of the motor or the mechanism effecting movement. Typically, if clamping or firing fails the force output of the driving motor drops below a minimum acceptable, such as from an absence of material between clamping jaws, or the force output may spike above a maximum acceptable force, such as from clamping on a bone or jamming of the mechanism. Continuing driving of the motor in either case may result in damage to surrounding materials or tissue. By monitoring the force output of the driving motor during clamping of the material and/or firing into the tissue, the claimed methods and systems detect failure or likely failure during clamping or firing and output an indication of such failure or likely failure to the user. Additionally, the system and methods may automatically terminate the clamping or firing or wait for further input from the user after providing an indication of failure. Ideally, the methods include monitoring a drive parameter during clamping or staple firing, and providing an indication of the likelihood of clamping or firing failure in response to the monitored drive parameter.

Minimally Invasive Robotic Surgery

Referring now to the drawings, in which like reference numerals represent like parts throughout the several views, FIG. 1 is a plan view illustration of an embodiment of the present invention. FIG. 1 illustrates a Minimally Invasive Robotic Surgical (MIRS) system 10, typically used for performing a minimally invasive diagnostic or surgical procedure on a Patient 12 who is lying down on an Operating table 14. The system can include a Surgeon's Console 16 for use by a Surgeon 18 during the procedure. One or more Assistants 20 may also participate in the procedure. The MIRS system 10 can further include a Patient Side Cart 22 (surgical robot), and an Electronics Cart 24. The Patient Side Cart 22 can manipulate at least one removably coupled tool assembly 26 (hereinafter simply referred to as a “tool”) through a minimally invasive incision in the body of the Patient 12 while the Surgeon 18 views the surgical site through the Console 16. Tool assembly 26 includes end effector 25, the end effector having jaws for clamping the tissue and a mechanism for firing a staple through the clamped tissue. An image of the surgical site can be obtained by an endoscope 28, such as a stereoscopic endoscope, which can be manipulated by the Patient Side Cart 22 so as to orient the endoscope 28. The Electronics Cart 24 can be used to process the images of the surgical site for subsequent display to the Surgeon 18 through the Surgeon's Console 16. Electronics Cart 24 includes a Processor 27 for monitoring the drive parameter provided by the motor output to the end effector. Processor 27 may monitor the drive parameter by comparing the drive parameter to an acceptable range of drive parameters. As the acceptable range of drive parameters may vary with the displacement of the motor or the mechanism effecting movement of the end effector, the Processor 27 may also receive displacement data as to the displacement of the motor or the end effector mechanism during clamping and/or firing such that Processor 27 compares the monitored drive parameters against a range of acceptable drive parameters for any given displacement. The displacement data may be measured directly or may be determined from positional data, or derivatives thereof, obtained by the robotic system, such as a robotic patient-side manipulator (PSM) system, for example, described in U.S. Patent Application Publication No 2007/0005045, the entire contents of which are incorporated herein by reference. In response to the monitored drive parameter, Processor 27 may output a clamping failure indication to a user interface. The system 10 then communicates an indicator of the prediction to the physician on the Surgeon's Console 16 so as to communicate to the surgeon whether clamping or firing has failed.

FIG. 2 is a perspective view of the Surgeon's Console 16. The Surgeon's Console 16 includes a left eye display 32 and a right eye display 34 for presenting the Surgeon 18 with a coordinated stereo view of the surgical site that enables depth perception. The Console 16 further includes one or more input control devices 36, which in turn cause the Patient Side Cart 22 (shown in FIG. 1 ) to manipulate one or more tools. The input control devices 36 will provide the same degrees of freedom as their associated tools 26 (shown in FIG. 1 ) so as to provide the Surgeon with telepresence, or the perception that the input control devices 36 are integral with the tools 26 so that the Surgeon has a strong sense of directly controlling the tools 26. To this end, position, force, and tactile feedback sensors (not shown) may be employed to transmit position, force, and tactile sensations from the tools 26 back to the Surgeon's hands through the input control devices 36.

The Surgeon's Console 16 is usually located in the same room as the patient so that the Surgeon may directly monitor the procedure, be physically present if necessary, and speak to an Assistant directly rather than over the telephone or other communication medium. However, the Surgeon can be located in a different room, a completely different building, or other remote location from the Patient allowing for remote surgical procedures (i.e., operating from outside the sterile field).

FIG. 3 is a perspective view of the Electronics Cart 24. The Electronics Cart 24 can be coupled with the endoscope 28 and can include Processor 27 to monitor the drive parameter and to determine an indication of clamping failure in response to the monitored drive parameter. Processor 27 may also process captured images for subsequent display, such as to a Surgeon on the Surgeon's Console, or on any other suitable display located locally and/or remotely.

FIG. 4 diagrammatically illustrates a robotic surgery system 50 (such as MIRS system 10 of FIG. 1 ), in which the Processor 58 and Display 60 are depicted separately from Electronics Cart 56 and Surgeon's Console 52. As discussed above, a Surgeon's Console 52 (such as Surgeon's Console 16 in FIG. 1 ) can be used by a Surgeon to control a Patient Side Cart (Surgical Robot) 54 (such as Patent Side Cart 22 in FIG. 1 ) during a minimally invasive procedure. In preparation for firing a staple to seal a body tissue, the Surgeon can command the tool of the Patient Side Cart 54 to clamp between jaw members of an end effector. In response to this command, Processor 58 can command the system to begin driving the motor to engage a mechanism that begins moving the jaws together and increase a clamping force to a desired clamping force. As the jaws begin moving together and the clamping force increases, the Processor 58 continuously monitors a drive parameter of the motor and compares the drive parameter to an acceptable range of drive parameters as the motor drives the jaws to clamp at a desired clamping force. If at any point during clamping, the drive parameter exceeds or drops below an acceptable drive parameter, Processor 58 may output the indication of clamping failure on the user interface. In response to detection of clamping failure, Processor 58 may also command additional functions, such as suspending driving of the motor, preventing firing of the staple, maintaining the clamping force at the point of detected clamping failure, waiting for user input, and unclamping the tissue. Similarly, the Processor 58 continuously monitors the drive parameter during firing of a staple through successfully clamped tissue. In response to the drive parameter falling outside the acceptable range of desired drive parameters, Processor 58 may output a failure indication on the user interface. In response to detected firing failure, Processor 58 may command other functions, such as terminating firing, suspending driving of the motor, maintaining clamping of the tissue while preventing firing, or waiting for user input.

One of skill in the art would appreciate that an indication of clamping failure may include an indication of how likely clamping failure may be. For example, the Processor 58 may output an indication of clamping failure indicating the likelihood of clamping failure from a 0% chance of failure to a 100% chance of failure, thus allowing the user to adjust or terminate the procedure before actual failure occurs based on an increase in the likelihood of failure as indicated by the failure indication. In some embodiments, if the monitored drive parameter is within the acceptable range of drive parameters, then a failure indicator that express a likelihood of failure may express a likelihood of failure that falls within a range of 0 to 49%. In another embodiment, this range may be expressed as a gradient, including a non-numerical gradient, such as a color gradient. Depending on the likelihood of failure as communicated by the failure indicator, the Surgeon may then safely proceed with clamping of the body tissue or may abort clamping and reposition the jaws until Display 60 indicates a higher likelihood of clamping or firing success.

FIGS. 5A and 5B show a Patient Side Cart 22 and a surgical tool 62, respectively. The surgical tool 62, one of the surgical tools 26, is an example of an end effector having a set of jaw members for clamping a tissue and firing a staple into the clamped tissue. The Patient Side Cart 22 shown provides for the manipulation of three surgical tools 26 and an imaging device 28, such as a stereoscopic endoscope used for the capture of images of the site of the procedure. Manipulation is provided by robotic mechanisms having a number of robotic joints. The imaging device 28 and the surgical tools 26 can be positioned and manipulated through incisions in the patient so that a kinematic remote center is maintained at the incision so as to minimize the size of the incision. Images of the surgical site can include images of the distal ends of the surgical tools 26 when they are positioned within the field-of-view of the imaging device 28.

Tissue Clamping and Staple Firing With Independent Actuation Mechanisms

In many embodiments, two independent actuation mechanisms are used to control the articulation of an articulated jaw of an end effector. A first actuation mechanism can be used to provide a high force clamping mode, and a second actuation mechanism can be used to provide a high force firing mode. In many embodiments, the first and second actuation mechanism used to provide the high clamping force and high firing force is non-back-drivable. The first and second actuation mechanisms may comprise a first and second leadscrew. Using independent actuation mechanisms may be beneficial in some surgical applications, for example, electrocautery sealing, stapling, etc., that may require different forces for different functions during the same procedure.

In many embodiments, actuation of the jaws in the high clamping force mode is provided by a leadscrew actuation mechanism that includes a leadscrew driven cam. The driven cam interfaces with a mating cam surface on the articulated jaw so as to hold the articulated jaw in a closed (clamped) configuration when the leadscrew driven cam is at a first end of its range of motion. In addition, the driven cam does not constrain motion of the articulated jaw when the leadscrew driven cam is at a second end (opposite end) of its range of motion. In other words, the mating cam surfaces are arranged such that motion of the leadscrew driven cam in one direction will cause the articulated jaw to close, and motion of the leadscrew driven cam in the reverse direction will allow (but not force) the articulated jaw to open to a limit provided by the cam surfaces. Often, the leadscrew actuation mechanism is non-back-drivable. In many embodiments, the position of the jaw members of the end effector can be determined by the position of the cable actuation mechanism, or if driven by a leadscrew, the position of the leadscrew. The system may include a dual drive motor having a drive for effecting clamping at a clamping force and a drive for effecting firing a staple at a firing force. The motor may utilize an existing motor or drive, or utilize an additional drive or motor, to effect firing of the staple. The claimed methods and systems monitor the drive parameter of whichever motor, or motors, which are driving the clamping or firing. Additionally, terminating or stopping driving of the motor when failure is detected may also comprise continuing driving of another drive or motor effecting another function. For example, if firing failure is indicated, the system may stop driving the firing force, while still maintaining the driving of the clamping force and wait for a user to unclamp the tissue.

FIG. 6A is a perspective view of an end effector 70 having a jaw 72 articulated by two independent actuation mechanisms, in accordance with many embodiments. The end effector 70 includes an end effector base 74, the articulated jaw 72, and a detachable stationary jaw 76, which holds the staples. The end effector 70 is actuated via a first drive shaft 78, a second drive shaft 80, and two actuation cables (not shown). The first drive shaft 78 rotates a leadscrew 82 of a leadscrew actuation mechanism, the leadscrew 82 located within the stationary jaw 76. The second drive shaft 80 rotates another leadscrew (not shown) of the detachable stationary jaw 76.

In many embodiments, the first drive shaft 78 and/or the second drive shaft 80 are driven by drive features located in a proximal tool chassis to which the end effector 70 is coupled with via an instrument shaft. In many embodiments, the proximal tool chassis is configured to be releasably mountable to a robotic tool manipulator. In many embodiments, the first drive shaft 78 and the second drive shaft 80 are actuated via respective drive features located in the proximal tool chassis. In many embodiments, such drive features are driven by motors that are located in the proximal tool chassis.

FIG. 6B is a perspective view of the end effector 70 of FIG. 6A (with the articulated jaw 72 removed to better illustrate components of the leadscrew actuation mechanism), in accordance with many embodiments. The leadscrew 82 is mounted for rotation relative to the end effector base 74. A leadscrew driven cam 84 is coupled with the leadscrew 82 so that selective rotation of the leadscrew 82 can be used to selectively translate the leadscrew driven cam 84 along a cam slot 86 in the end effector base 74. The end effector 70 includes a pivot pin 88 that is used to rotationally couple the articulated jaw 72 with the end effector base 74.

FIGS. 7A through-10 illustrate the actuation mechanisms by which an end effector clamps a body tissue between its jaws clamping mode and fires a staple into the clamped tissue.

FIGS. 7A and 7B illustrate the leadscrew actuation mechanism of FIGS. 6A and 6B. The leadscrew 82 has a distal journal surface 96 and a proximal journal surface that interfaces with a proximal bearing 98. In many embodiments, the distal journal surface 96 is received within a cylindrical receptacle located at the distal end of the cam slot 86. Such a distal support for the leadscrew 82 can be configured to keep the leadscrew 82 from swinging excessively, and with relatively large clearance(s) between the distal journal surface 96 and the cylindrical receptacle. The proximal bearing 98 is supported by the end effector base 74 so as to support the proximal end of the leadscrew 82. The proximal bearing 98 can be a ball bearing, which may help to reduce friction and wear. A distal bearing (not shown) can be supported by the end effector base 74 so as to support the distal end of the leadscrew 82, and the distal bearing can be a ball bearing. The leadscrew driven cam 84 includes a threaded bore configured to mate with the external threads of the leadscrew 82. The leadscrew driven cam 84 includes top and bottom surfaces configured to interact with corresponding top and bottom surfaces of the cam slot 86. The interaction between leadscrew driven cam 84 and the cam slot 86 prevents the leadscrew driven cam 84 from rotating relative to the cam slot 86, which causes the leadscrew driven cam 84 to translate along the cam slot 86 in response to rotation of the leadscrew.

The articulated jaw 72 includes mating cam surfaces 94 that are configured so that the position of the leadscrew driven cam 84 along the cam slot 86 determines the extent to which the rotational motion of the articulated jaw 72 around the pivot pin 88 is constrained by the leadscrew driven cam 84. The articulated jaw 72 includes a first proximal side 100 and a second proximal side 102 that are separated by a central slot. The first and second proximal sides are disposed on opposing sides of the end effector base 74 when the articulated jaw 72 is coupled with the end effector base 74 via the pivot pin 88. Each of the first and second proximal sides 100, 102 includes a recessed area defining a mating cam surface 94 and providing clearance between the leadscrew driven cam 84 and the proximal sides 100, 102. When the leadscrew driven cam 84 is positioned at or near the proximal end of the cam slot 86 (near its position illustrated in FIGS. 7A and 7B), contact between the leadscrew driven cam 84 and the mating cam surfaces 94 of the articulated jaw 72 hold the articulated jaw in a clamped configuration. When the leadscrew driven cam 84 is positioned at the distal end of the cam slot 86, the rotational position of the articulated jaw around the pivot pin 88 is unconstrained by the leadscrew driven cam 84 for a range of rotational positions between a clamped configuration (where there is a gap between the leadscrew driven cam 84 and the mating cam surfaces 94 of the articulated jaw 72) and an open configuration (where there may or may not be a gap between the leadscrew driven cam 84 and the mating cam surfaces 94 of the articulated jaw 72). For positions of the leadscrew driven cam 84 in between the proximal and distal ends of the cam slot 86, the range of unconstrained motion can vary according to the cam surfaces used.

The use of a recess in each of the proximal sides 100, 102 to define the mating cam surfaces 94 of the articulated jaw 72 provides a number of benefits. For example, the use of recesses as opposed to traverse slots that extend through the proximal sides provides a continuous outside surface to the proximal sides 100, 102 of the articulated jaw, which is less likely to snag on patient tissue than would a traverse slot opening. The absence of traverse slots also helps to stiffen the proximal sides 100, 102 as compared to proximal sides with traverse slots, and therefore provides increased clamping stiffness. Such proximal sides 100, 102 may have increased stiffness in two planes, which may help maintain alignment of the articulated jaw 72 in the presences of external forces. Such increased stiffness in two planes may be beneficial in some surgical applications, for example, in tissue stapling where it is beneficial to maintain alignment between the staples and anvil pockets that form the staples. Further, the use of recesses instead of traverse slots also provides an actuation mechanism that is less likely to be jammed by extraneous material as compared to one having proximal sides with open traverse slots.

The leadscrew actuation mechanism can be configured to provide a desired clamping force between the articulated jaw and an opposing jaw of the end effector to facilitate cutting or sealing of the tissue. For example, in many embodiments, the leadscrew actuation mechanism is configured to provide at least 20 lbs of clamping force at the tip of the articulated jaw 72 (approximately 2 inches from the pivot pin 88). In many embodiments, the leadscrew actuation mechanism is configured to provide at least 50 lbs of clamping force at the tip of the articulated jaw 72. In many embodiments, to produce 50 lbs of clamping force at the tip of the articulated jaw 72, the input torque to the leadscrew 82 is approximately 0.2 N m and the leadscrew 82 has 29 turns. The system may detect the displacement of the motor, of the clamping or firing mechanism or the configuration of the end effector by sensing the displacement of the leadscrew. For example, in many embodiments, the system is calibrated before starting the procedure so as to determine the range of motion of both the clamping and the firing mechanism and the displacement of the leadscrew within that range of motion. Such calibration allows the system to determine the configuration of the end effector or the displacement of the mechanism solely from the displacement of the leadscrew.

The leadscrew actuation mechanism can be fabricated using available materials and components. For example, many components of the leadscrew actuation mechanism can be fabricated from an available stainless steel(s). The leadscrew driven cam 84 can be coated (e.g., TiN) to reduce friction against the surfaces it rubs against (e.g., leadscrew 82; end effector base 74; proximal sides 100, 102 of the articulated jaw 72). Stranded cables can be used to drive the first actuation mechanism.

FIGS. 8A through 8F illustrate components of a cable actuation mechanism 110, in accordance with many embodiments. As described above, the leadscrew driven cam 84 can be positioned at the distal end of the cam slot 86 (i.e., near the pivot pin 88). For such a distal position of the leadscrew driven cam 84, as discussed above, the rotational position of the articulated jaw 72 about the pivot pin 88 is unconstrained for a range of rotational positions of the articulated jaw 72. Accordingly, the rotational position of the articulated jaw 72 about the pivot pin 88 can be controlled by the cable actuation mechanism 110. The cable actuation mechanism 110 is operable to vary the rotational position of the articulated jaw between the clamped configuration and the open configuration. The cable actuation mechanism 110 includes a pair of pull cables 112, 114. The cable actuation mechanism 110 also includes a first linkage 116 that is used to rotate the articulated jaw 72 about the pivot pin 88 towards the clamped configuration, and an analogous second linkage 118 that is used to rotate the articulated jaw 72 about the pivot pin 88 towards the open configuration. The first linkage 116 (shown in FIGS. 8A and 8B) includes a rotary link 120 that is mounted for rotation relative to the end effector base 74 via a pivot pin 122. A connecting link 124 couples the rotary link 120 to the articulated jaw 72 via a pivot pin 126 and a pivot pin 128. The first linkage 116 is articulated via a pulling motion of the pull cable 112. In operation, a pulling motion of the pull cable 112 rotates the rotary link 120 in a clockwise direction about the pivot pin 122. The resulting motion of the connecting link 124 rotates the articulated jaw 72 in a counter-clockwise direction about the pivot pin 88 towards the clamped configuration.

The second linkage 118 (shown in FIGS. 8C through 8F) of the cable actuation mechanism 110 includes analogous components to the first linkage 116, for example, a rotary link 130 mounted for rotation relative to the end effector base 74 via a pivot pin 132, and a connecting link 134 that couples the rotary link 130 to the articulated jaw 72 via two pivot pins 136, 138. The second linkage 118 is articulated via a pulling motion of the pull cable 114. The second linkage 118 is configured such that a pulling motion of the pull cable 114 rotates the articulated jaw 72 about the pivot pin 88 towards the open configuration. In many embodiments, the pivot pin 136 between the connecting link 134 and the rotary link 130 of the second linkage 118 is 180 degrees out of phase with the pivot pin 126 between the connecting link 124 and the rotary link 120 of the first linkage 116. Coordinated pulling and extension of the pull cables 112, 114 of the cable actuation mechanism 110 is used to articulate the articulated jaw 72 between the open and clamped configurations. In order to best provide equal and opposite cable motion (and thereby maintain cable tension in a capstan-driven system described below), a common rotational axis for the pivot pins 122, 132 is configured to lie on a plane that contains the rotational axes for pivot pins 128, 138 when the articulated jaw 72 is closed (or nearly closed) and again when the when the articulated jaw 72 is open (or nearly open). The connecting links 124, 134 are assembled symmetrically opposite about this same plane for the first and second linkages 116, 118. The distance between the pivot pins 122, 126 and between the pivot pins 132, 136 is the same for both the first and second linkages 116, 118, and the distance between the pivot pins 126, 128 and between the pivot pins 136, 138 is the same for both the first and second linkages 116, 118.

FIGS. 9A and 9B illustrate an articulation of the articulated jaw 72 via another cable actuation mechanism 140, in accordance with many embodiments. In embodiment 140 of the cable actuation mechanism, a first pull cable 142 and a second pull cable 144 are directly coupled with the proximal end of the articulated jaw 72. The first pull cable 142 wraps around a first pulley 146 so that a pulling motion of the first pull cable 142 rotates the articulated jaw 72 about the pivot pin 88 towards the clamped configuration. The second pull cable 144 wraps around a second pulley 148 so that a pulling motion of the second pull cable 144 rotates the articulated jaw 72 about the pivot pin 88 towards the open configuration. Accordingly, coordinated pulling and extension of the first and second pull cables of the cable actuation mechanism 140 is used to articulate the articulated jaw 72 between the open and clamped configurations. In order to best provide equal and opposite cable motion (and thereby maintain cable tension in the capstan-driven system described below), the radius of the arc prescribed by cable 142 about the pivot 88 is substantially the same as the radius prescribed by cable 144 about the pivot 88.

Although the mechanisms may comprise leadscrews, cable or hypotubes, alternate mechanisms can be used to effect clamping or staple firing. For example, an actuation mechanism comprising push/pull rods or springs can be used.

FIG. 10 is a cross-sectional view illustrating components of the above discussed leadscrew actuation mechanism. The illustrated components include the leadscrew 82, the leadscrew driven cam 84, the cam slot 86 in the end effector base 74, the distal journal surface 96, the cylindrical receptacle 154 in the end effector base, and the proximal bearing 98 supported by the end effector base 74.

FIG. 11 is a simplified diagrammatic illustration of a tool assembly 170, in accordance with many embodiments. The tool assembly 170 includes a proximal actuation mechanism 172, an elongate shaft 174 having a proximal end and a distal end, a tool body 176 disposed at the distal end of the shaft, a jaw 178 movable relative to the tool body 176 between a clamped configuration and an open configuration, a first actuation mechanism coupled with the jaw, and a second actuation mechanism coupled with the jaw. The first actuation mechanism is operable to vary the position of the jaw relative to the tool body between the clamped configuration and the open configuration. The second actuation mechanism has a first configuration where the jaw is held in the clamped configuration and a second configuration where the position of the jaw relative to the tool body is unconstrained by the second actuation mechanism. The first actuation mechanism is operatively coupled with the proximal actuation mechanism. In many embodiments, the first actuation mechanism comprises a pair of pull cables that are actuated by the proximal actuation mechanism. The second actuation mechanism is operatively coupled with the proximal actuation mechanism. In many embodiments, the second actuation mechanism includes a leadscrew driven cam located in the tool body that is driven by the proximal actuation mechanism via a drive shaft extending through the elongate shaft 174 from the proximal actuation mechanism.

The tool assembly 170 can be configured for use in a variety of applications. For example, the tool assembly 170 can be configured as a hand held device with manual and/or automated actuation used in the proximal actuation mechanism. The tool assembly 170 can also be configured for use in surgical applications, for example, electrocautery sealing, stapling, etc. The tool assembly 170 can have applications beyond minimally invasive robotic surgery, for example, non-robotic minimally invasive surgery, non-minimally invasive robotic surgery, non-robotic non-minimally invasive surgery, as well as other applications where the use of the disclosed redundant jaw actuation would be beneficial.

Redundant jaw actuation can be used to articulate a jaw of a robotic tool end effector. For example, FIG. 12 schematically illustrates a robotic tool 180 employing redundant jaw actuation. The robotic tool 180 includes a proximal tool chassis 182, a drive motor 184, an instrument shaft 186, a distal end effector 188, a first actuation mechanism portion 190, and a second actuation mechanism 192. The distal end effector 188 comprises an articulated jaw 194. The proximal tool chassis 182 is releasably mountable to a robotic tool manipulator 196 having a first drive 198, and a first actuation mechanism portion 200 that operatively couples with the first actuation mechanism portion 190 of the robotic tool 180 when the proximal tool chassis 182 is mounted to the robotic tool manipulator 196. The instrument shaft 186 has a proximal end adjacent the tool chassis 182, and a distal end adjacent the end effector 188. The first actuation mechanism (comprising portion 200 and portion 190) couples the first drive 198 to the articulated jaw 194 when the tool chassis 182 is mounted to the tool manipulator 196 so as to articulate the end effector 188 between an open configuration and a clamped configuration. The second actuation mechanism 192 couples the drive motor 184 to the articulated jaw 194 so as to apply a firing force to a staple so as to fire the staple from the end effector through the tissue clamped within the jaws of the end effector. The first actuation mechanism can be a leadscrew-driven mechanism that provides relatively high forces so as to fire the staple through the tissue. The second actuation mechanism can include a drive shaft that couples the drive motor 184 with a leadscrew actuation mechanism, for example, an above discussed leadscrew actuation mechanism that provides the high clamping force mode. System 180 includes Sensor 193 for monitoring the drive parameters of the first drive 198 and the drive motor 184 during clamping and firing, respectively. Sensor 193 may also detect the displacement of the first drive and the drive motor so as to determine the acceptable range of desired drive parameters according to a given displacement of the motor or configuration of the end effector. The configurations of the end effector in a clamping mode may include an open configuration, a close/clamped configuration and any configuration therebetween. The configurations of the end effector in the firing mode may include a pre-firing configuration in which one or more staples are disposed within the end effector and releasably coupled with the drive motor 184 through a mechanism and a post-firing configuration where one or more staples have been fired through the tissue, and typically bent so as to seal the tissue, the staple having been released from the end effector. The configurations of the end effector may also include any configuration in between the pre-firing and post-firing mode. By detecting the displacement of the first drive or drive motor, the sensor can determine a given configuration of the end effector in either mode, so as to more accurately determine the acceptable range of driving parameters and predict failure of clamping or firing.

FIG. 13 is a diagrammatic view of a telerobotic surgical system which incorporates an embodiment of the present invention. In the example of FIG. 13 , a physician inputs a command to the system to clamp a tissue or fire a staple. In response to the user command, the system begins driving the motor 210 so as to drive clamping or firing through the clamping and/or firing mechanism 240. As mechanism 240 effects clamping or firing, Processor 220 monitors a drive parameter, such a torque output, of Motor 210. Monitoring may comprise comparing the torque output to an acceptable range of torque outputs for a given displacement of the motor or mechanism. The Processor 220 may be coupled to any or all of the Motor 210, the Mechanism 240 or a Sensor 230 for detecting a displacement of the motor or mechanism during the clamping or firing. In response to the monitored drive parameter falling outside an acceptable range of torque outputs (or displacements of the driving mechanism), Processor 220 outputs a Failure Indication 250 on Display 60 of the user interface, indicating that clamping or firing has failed, or a likelihood of failure. Typically, Display 60 includes images of the end effector during clamping or firing.

FIGS. 14A-14B illustrate two examples of failure indicator 250 that may appear on Display 60 of System 10. Typically, the user interface Display 60 images and/or visual representations of the surgical tool end effectors during the surgery in addition to the indicators of clamping or fairing failure. The failure indicator may be superimposed over the images on the user interface display during the surgical procedure so as to seamlessly incorporate the features of the claimed invention into the surgical procedure. Preferably, the failure indicator only appears when the Surgeon has commanded System 10 to clamp or fire a staple into a clamped tissue. By monitoring the drive parameter, System 10 provides an indication of failure during the procedure. FIG. 14A depicts Display 60 with a clamping failure indicator 250 superimposed on the lower right area of the screen, wherein the failure indicator 250 indicates that clamping success is likely and that the system is proceeding to clamp. FIG. 15B depicts Display 60 with failure indicator 250 superimposed on the lower right area of the screen, wherein the indicator indicates that clamping will likely fail. Failure indicator 250 is output in response to the monitored drive parameter driving the clamping being outside the predetermined range of acceptable drive parameters.

FIG. 15A-15B illustrate additional examples of the clamping prediction indicator 250. FIG. 15A depicts an example of a failure indicator showing a likelihood of clamping failure as a gradient, where in this example, the likelihood is expressed as a percentage of chance. For example, the further outside the range of predetermined drive parameters the actual monitored drive parameter is, the more likely clamping failure will be. For example, in one embodiment, if the actual monitored driving torque is within 5% of a predetermined target driving torque, the system will display an indicator of 90% likelihood of clamping success. As the monitored driving torque further diverges from the target driving torque, the likelihood decreases in a monotonic relationship, such as from 90% down to a 0% likelihood of clamping. Alternatively, the driving parameter may be the displacement of the driving mechanism. In such an embodiment, the system may monitor the displacement of the driving mechanism and indicate clamping or firing failure when the displacement is outside a predetermined range of acceptable displacements. FIG. 15B depicts an embodiment having an indicator which toggles between two settings. When the light of the indicator is lit, likely firing failure is indicated, otherwise firing failure is not indicated.

FIGS. 16A-16B illustrate graphs of a monitored drive parameter in relation to an acceptable range of desired drive parameters, in accordance with many embodiments of the invention. This embodiment illustrates that the system may provide an indication of clamping and/or firing failure simply from monitoring the torque of the motor as it drives the clamping or firing of the system. As shown, the predetermined range of torques may vary in relation to the displacement of the motor as it effects movement of the end effector. The displacement (s) of the motor may be correlated by the system to a position of the end effector during the clamping process. For example, during clamping, as the displacement of the motor moves from s_(i) to s_(f), the jaws of the end effector move from an open configuration to a closed (clamped) configuration. Similarly, the motor displacement may be used to track the position or configuration of the end effector during firing of a staple into the clamped tissue. In many embodiments, before performing a procedure, the system calibrates the jaws of the end effector from a first to a second configuration, such as calibrating jaws from an open position to a closed position, so as to correlate the displacement of the motor with the configuration of the end effector.

FIG. 16A illustrates a predetermined range of acceptable driving torques (t) which vary with motor displacement (s). The range is delimited by two functions, an upper boundary t_(upper) and a lower boundary t_(lower). The system outputs an indication of clamping failure in response to the monitored driving torque T as compared to the predetermined range of acceptable driving torques. If the displacement of the motor reaches s_(f) and the system has not indicated likely clamping or firing failure, the system may provide an indication of successful clamping or firing. In this example, the graph depicts the acceptable range of torques and the monitored driving torque during clamping or firing as T1. As shown, during the clamping or firing, T1 remains within the acceptable range of driving torques, thus the system would output an indication that clamping or firing is likely successful (which may include a lack of an indication of failure).

FIG. 16B illustrates a similar predetermined range of acceptable driving torques (t) and two separate driving torques, T2 and T3 (occurring at different times). As shown, T2 falls below the lower boundary, t_(lower), of the acceptable range of torques. This may occur where the tissue has slipped out of the jaws of the end effector and less torque is required to close the jaws since there is no tissue between the jaws. In such case, the system would output an indication of likely clamping failure at Failure Point F2, at which point the system may suspend driving of the clamping to prevent any possible tissue damage from continuing to apply the clamping force after failure occurs. Failure may also occur if the driving torque exceeds the upper boundary of the range of acceptable torques, as shown by monitored torque T3. This may occur where jaws have clamped onto a bone and an excessive amount of torque is required to reach the closed/clamped configuration, which may potentially cause tissue damage to the bone or surrounding tissue. In this example, the monitored torque exceeds t_(upper) at Failure Point F3, at which point the system may suspend driving of the clamping or firing to reduce the likelihood of tissue damage. In response to detection of failure, the system may suspend driving of the drive parameter or reverse the driving force to unclamp the tissue, in addition to providing an indication of failure.

FIGS. 17-19 graphically illustrate embodiments of the claimed methods. FIG. 17 is a simplified representation of exemplary method 300. Method 300 includes a step 302 of monitoring a drive parameter of a motor driving a tool to clamp and a step 304 of outputting an indication on a user interface of a likelihood of clamping failure during clamping in response to the monitored drive parameter. FIG. 18 is a simplified representation of exemplary method 304. Method 304 includes a step 305 of monitoring a drive parameter of a motor driving a tool to fire a staple into a clamped material and a step 307 of outputting an indication on a user interface of a likelihood of firing failure during firing in response to the monitored drive parameter. FIG. 19 is a simplified representation of a method 310 which further includes the step 312 of driving a motor to clamp a tissue in response to a user input to clamp, a step 314 of monitoring a drive parameter of the motor during clamping of the tissue, a step 316 of outputting an indication of a likelihood of clamping failure during clamping in response to the monitored drive parameter, and a step 318 of suspending driving of the motor if there is an indication of likely failure or continuing driving of the motor if there is no indication of likely failure. FIG. 20 is a simplified representation of a method 320 which includes step 322 of driving a motor to clamp or fire a staple into a clamped material in response to a user input, step 324 of monitoring a drive parameter during clamping or firing, step 326 of outputting an indication on a user interface of the likelihood of clamping or firing failure during clamping or firing. If there is no indication of likely failure, then the method of 320 further includes step 328 of continuing driving the motor to clamp or fire and step 330 of outputting a message of success when clamping or firing complete. If there is an indication of likely failure, then the method of 320 further includes step 332 of suspending driving of the motor in response to the indication and step 334 of outputting an indication that the driving parameter has been suspended.

FIGS. 21-22 depict flowcharts illustrating embodiments of the claimed methods. FIG. 21 is a flow chart showing an embodiment of the claimed method as applied to clamping as it would be incorporated into a minimally invasive robotic surgical system. FIG. 22 is a flow chart showing an embodiment of the claimed method as applied to firing of a staple into clamped tissue as it would be incorporated into the robotic surgical system of FIG. 20 . The described robotic system may require user input to command the system to clamp and/or firing the staple into the clamped tissue.

It is understood that the examples and embodiments described herein are for illustrative purposes and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and the scope of the appended claims. Numerous different combinations are possible, and such combinations are considered to be part of the present invention. 

What is claimed is:
 1. An apparatus comprising: an end effector comprising a first jaw and a second jaw; a drive system configured to apply a force or torque to cause staple firing to occur; and a processor configured to: monitor a drive parameter of the drive system while the drive system applies the force or torque to cause staple firing to occur; and maintain application of clamping by the first jaw and the second jaw while suspending application of the force or torque that causes the staple firing, when the drive parameter indicates failure during the staple firing.
 2. The apparatus of claim 1, wherein the processor is further configured to: monitor a displacement of the drive system; determine an acceptable range of force or torque based on the displacement of the drive system; and determine that the drive parameter indicates failure during staple firing by determining that the applied force or torque is outside of the acceptable range of force or torque.
 3. The apparatus of claim 1, wherein the processor is further configured to: determine a position of the jaws; and control application of the force or torque by the drive system based on the position of the jaws.
 4. The apparatus of claim 1, wherein the processor is further configured to output, to a user, an indicator based on the monitoring.
 5. The apparatus of claim 4, wherein the indicator is of a likelihood of stapling failure.
 6. The apparatus of claim 5, wherein the indicator comprises any or all of an audio, a visual, or other sensory indicator for communicating the stapling failure to the user.
 7. The apparatus of claim 1, wherein the drive system comprises any or all of a cable, a hypotube, a drive shaft, and a leadscrew.
 8. The apparatus of claim 1, wherein a monitored force or torque that is greater than a maximum acceptable force or torque is indicative of jamming.
 9. The apparatus of claim 1, wherein the processor is further configured to terminate the application of the clamping by the first jaw and the second jaw in response to the applied force or torque being less than a lower limit of an acceptable range of force or torque.
 10. The apparatus of claim 1, wherein the processor is further configured to reverse a direction of the application of the force or torque by the drive system in response to the applied force or torque being less than a lower limit of an acceptable range of force or torque.
 11. The apparatus of claim 1, wherein the application of the force or torque by the drive system causes a staple to fire through a clamped tissue.
 12. A method comprising: monitoring, by a processor, a drive parameter of a drive system to an end effector comprising a first jaw and a second jaw, wherein application of force or torque by the drive system to the end effector causes staple firing to occur; and maintaining, by the processor, application of clamping by the first jaw and the second jaw while suspending application of the force or torque that causes the staple firing, when the drive parameter indicates failure during the staple firing.
 13. The method of claim 12, further comprising: monitoring, by the processor, a displacement of the drive system; determining, by the processor, an acceptable range of force or torque based on the displacement of the drive system; and determining that the drive parameter indicates failure during staple firing by determining that the force or torque applied by the drive system to cause staple firing is outside of the acceptable range of force or torque.
 14. The method of claim 12, further comprising: determining, by the processor, a position of the jaws; and controlling, by the processor, application of the force or torque by the drive system based on the position of the jaws.
 15. The method of claim 12, further comprising outputting, by the processor to a user, an indicator based on the monitoring.
 16. The method of claim 15, wherein the indicator is of a likelihood of stapling failure.
 17. The method of claim 16, wherein the indicator comprises any or all of an audio, a visual, or other sensory indicator for communicating the stapling failure to the user.
 18. The method of claim 12, wherein a monitored force or torque that is greater than a maximum acceptable force or torque is indicative of jamming.
 19. The method of claim 12, further comprising terminating, by the processor, the application of the clamping by the first jaw and the second jaw in response to the force or torque applied by the drive system to cause staple firing being less than a lower limit of an acceptable range of force or torque.
 20. The method of claim 12, further comprising reversing, by the processor, a direction of the application of the force or torque by the drive system in response to the force or torque applied by the drive system to cause staple firing being less than a lower limit of an acceptable range of force or torque. 